134 FRIDTJOF NANSEN. 



I had also several water-bottles made for attaching to the 

 sounding line at intermediate depths. One of these water-bottles 

 was composed of two brass tubes about 1 m. long and 2 cm. in 

 diameter (PI. 2, Fig. 5). The tubes had stop-cocks at both ends, 

 similar to those used for the Buchanan Stopcock Waterbottle ^. 

 The arms of the stop-cocks are united by a rod, so that the 

 tubes are movable up and down on both sides of this rod, which 

 has at its upper end a slipping arrangement with propeller. When 

 the tubes are lifted and attached by their upper ends to the 

 hooks which are set by the propeller, the stop-cocks are open, 

 and during the passage down the water may course freely through 

 the tubes, being considerably assisted by the conical mouth-pieces 

 at their lower ends. As the diameter of the apertures of the open 

 stop-cocks is the same as that of the tubes, the water in the latter, 

 even without these mouth-pieces, would be changed with almost 

 equal rapidity as the instrument descends through the water, 

 the water only being hindered by the friction against the sides 

 of the tubes. When the instrument is hauled up the propeller 

 will release a hook, on the same principle as that used for the 

 insulated water-bottle (see above); the tubes are then free, and 

 will fall down by their own weight on both sides, to their lower 

 positions, and thus close the stop-cocks. By two small stop- 

 springs the tubes are now prevented from again being lifted. 

 At the lower end of the tubes there is a small stop-cock for 

 taking the water-sample and at the upper end is a small 

 screw with a hole which can be opened for letting in air. 

 In this screw there is also a small safety-valve consisting of 

 a fine hole over which an india-rubber bladder is tied at the 

 end of the screw to make it water tight. When the water 

 expands by being hauled up from great depths, the superfluous 

 water may escape through the hole into the bladder. 



By two screws at the upper and lower ends of the central 



1 Challenger Beport, Narrative, vol. I, Part 1, p. 113. 



